Claspless partial denture axial retainer construction

ABSTRACT

A claspless partial denture having an elongated resilient member or cantilever spring in substantially L-shaped form in which the horizontal portion is affixed to the saddle beneath an end tooth and the vertical portion extends along said end tooth but is not connected thereto. The horizontal portion of the spring carries a male member which telescopingly interlocks in a female slot or channel member in the crown abutment which opens through the occlusal and gingival surfaces thereof and has a reduced throat which opens through one vertical face thereof, either the distal or mesial face, depending on the position of attachment of the partial denture. A bracing arm is carried by a strut of the saddle to one side of but unconnected to the vertical portion of the cantilever spring, the bracing arm being adapted to engage the crown abutment. The denture is adjustable, self-cleaning and absorbs displacement stresses.

United. States Patent [72] Inventor Arthur Ritter 1902 Chestnut St., Philadelphia, Pa. 19103 211 Appl. No. 885,217

[22] Filed Dec. 15, 1969 [45] Patented July 20, 1971 [54] CLASPLESS PARTIAL DENTURE AXIAL Primary Examiner- Robert Peshock AnomeyMcClure, Weiser & Millman ABSTRACT: A claspless partial denture having an elongated resilient member or cantilever spring in substantially L-shaped form in which the horizontal portion is affixed to the saddle beneath an end tooth and the vertical portion extends along said end tooth but is not connected thereto. The horizontal portion of the spring carries a male member which telescopingly interlocks in a femaleslot or channel member in the crown abutment which opens through the occlusal and gingival surfaces thereof and has a reduced throat which opens through one vertical face thereof, either the distal or mesial face, depending on the position of attachment of the partial denture. A bracing arm is carried by a strut of the saddle to one side of but unconnected to the vertical portion of the cantilever spring, the bracing arm being adapted to engage the crown abutment. The denture is adjustable, self-cleaning and absorbs displacement stresses.

y iii/"r111 j CLASPLESS PARTIAL DENTURE AXIAL RETAINER CONSTRUCTION This invention relates to removable partial denture constructions and constitutes an improvement over my US. Pat. No. 3,228,106.

in said patent, a resilient axial member or cantilever spring is provided which is substantially L-shaped, the horizontal portion of which is affixed to the saddle of the denture. The saddle includes an integral sleeve portion 50 which opposes thecrowned abutment tooth and the vertical portion of the spring extends vertically along the abutment surface of the sleeve portion but is. free to move relative thereto. The crowned abutment tooth is provided with an axial channel into whichv the vertical portion of the spring tits but in which it is not retained. The denture is actually retained on the abutment tooth by an arcuate clasp having integral axial struts which are received in complementary channels in the crowned abutment tooth, preferably 1-80 apart. The lower edge of the clasp is adapted to abut a. lingual'shoulder on the crowned abutment tooth to resist displacement of the denture toward thegingiva;

While the patented. device effectively serves toabsorb lateral; stresses. and any wear between the denture and the abutment tooth canbe compensatedbyv bending'the cantilever spring, nevertheless-the denture construction requires the use of'a clasp with struts that engage in complementary groovesin thecrowned. abutment tooth. for: retention; and cannot. be tissue-bearing in view oftheengagement of the. lower edgeof the clasp with thelingual:abutmentshoulder.

Theprimary. object of the, invention isto provide alclaspless ax-ialretention systemwhich .incorporates vthedesirable stressabsorbing and'adjustmentifeatures of. the patented structure butsimplifies its construction, manufacture andassembly.

A-n-.important1object.of the invention is to providev an axial denture retainer inwhich the-verticalportionof the L-shaped cantilever spring, as; above described,.is removably; retained-in a slot member whichextends thefullheightof the crowned abutment tooth thus eliminating the. need for. aclasp. with struts .to engage in'grooves in the abutmentwithout'sacrificing.

thestress-absorbing and .adjustmentfeaturesof thev spring.

Another objectof 'the invention is to provide'an axial partial denture retainer of the character described wherein the. denture may bewholly tissue'bearing to'eliminate. rotationaround the abutment: tooth and thus eliminatev stresses thereon. The instantdevice may, ofcourse, also be nontissue bearing, if desired.

Another object: of: the. invention is to provide a partial dentureconstruction incorporating-a cantilever springwhich is affixedto thesaddle of the denture and includes avertical portion having a male or flange-memberlwhich isremovably retained in a female slot member in the abutment'tooth, the latterrunningthe full height'oftheabutment tooth'and open topand, bottom, thus renderingth'edevice self-cleaning.

Another object of the; invention isto provideaa partial denture. constructionincorporating-a cantilever spring. which is affixedito the saddleofthe denture and includes avertical portionhavinga maleonflangemember which-is removably retained in.-.a female-slot memberiin the abutment toothin combination r-Wlth a.bracingyarmwhich engages but'is. not

locked itojheabutment tooth thus simplifyingthe procedure for adjusting the denture whenzthe male memberv becomes loose in the-female or slot member; si-nceall that is required is These and other-objects-of-the;-invention will-become apparent .as thefollowing descriptionxproceeds in conjunction withthe-accompanying drawings-wherein:

FIG, I is afragmentaryview ofthe human maxilla projected upon the occlusalpla'ne andillustratingthe present removable I denture construction'inplace,ready for use; FIG; ZQisanenlarged viewof the area. designated 2 inthe circular arrow on'FlG. l; I

FIG. 3 is a sectional view taken on the line 33 of H6. 2;

FlG. 4 is a view similar to FIG. 3 showing the denture disengaged from the abutment tooth but in position for engagement;

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 4;

FIG. 6 is an exploded perspective view of the male and female members of the invention; and I FIGS. 7-9 are profiles of alternative modifications of the male and female members.

Specific reference is now made to the drawings in which similar reference characters are used for corresponding ele-' ments throughout. The present partial denture 10 is removably mounted in the mandible 12 which may consist of natural or capped teeth 14, two of which 16 are abutment teeth which are suitably crowned as at 18. It is understood that while a particular type of'partial denture is herein shown, the same is merely illustrative and the principles of the invention are applicable to all types of partial dentures. Thus, for example, thepartial denture can fill in the space between'a crowned molar serving as one abutment tooth and a crowned incisor serving'asthe other abutment tooth, etc.

The denture is formedin a conventio'n'almanner and may be molded entirely of a suitable plastic, such as acrylic, in which artificial'teethare mounted or it may preferably be formed of a metal saddle 20'with' plastic 22 molded thereto in which the artificial" teeth 24 are mounted. Thoseartificial' teeth which oppose the abutmentteeth I6are'designated 26.

A resilientmember or cantileverspring 28 is provided which includes-a'metallic rod or-wire bent into substantially L- shaped' form to prod'ucea generallyhorizontal portion 30, a generally vertical portion'3 2 and an arcuate comer 34 joining them. The rod or wire may be solid or tubular and made of corrosion-resistant:springmetal. Preferably, the rod or wire is solid and: of circular or oval cross section and comprises platinumwith a'liigh' palladium content.

lntegral with or otherwise rigidly affixed to the vertical portion 32of the cantilever spring or wire and substantially coextensive therewith is a male member-36 formingat the juncture with'thewire'a' reducedneck p'ortion38'of width less than the diameter of the wire. Theneclcisin turn integral with or affixed toa flangemember fl), see FlGS. l 6, having flange portions 42' extending beyond-the-wire on both sides thereof, the-rear face-44 of theflangemembe'r beingflati Tlie:metallic:saddl'e 20 is formed'with'an upright strut'46 which extends'toone'sideof'tlie artificial tooth 26 andcarries atits upper end acurved bracin'g arm 48whichis'adapted to embrace'the abutment tooth16*asshown in FIGS; 1-3, the bracing: arm including also an arcuate portion 50 which is received in a suitable recess or groove 52 which' is'provided in a face portion of theartificial tooth 26"; I

Thehoriiontal portion 30 of the cantilever spring 28 is affixed, as-by;soldering1orwelding, to the upper surface of the metallic saddle 20; as-seen-in FIGS. 3 and 4, beneath the artificial'tooth 26' in such-aw-manner that-the curved corner 34 thereof'extendsoutside 'of the saddle at the strut 46 while the vertical portion 32 extends thefull height of the tooth 26 with theportion -36=bearin'g#against the-portion50 of the bracingarm'which' in turn'is'receivedin the recess 52 in the tooth 26$ A female member S t-is provided in the form of a metallic or plastic channel or slot m'emberwhich'is complementary to and coextensivelwiththemale or flange member 36. Accordingly, it includes-a rear'sub'stantially'flat wall 56, substantially perpendicular'sidewalls 58 and short front walls 60 which terminate in'a throat 62 only slightly widerthan the width of the neck 38 of themale memberand opening througha vertical face, distal or mesial, of the crown abutment depending upon where'the partial dentureis attached; Thus a vertical channel 64 is formed which'is open at the-topthrough the occlusal surface 65 'of the crown abutment and at the bottom through the gingival surface 66 of the crown abutment. The front walls 60 are continued-into short outwardlyflaringor divergent lips 67 Whenthe crown l8'of the'abutment tooth is still inits' wax up form, thefe'male member is'positioned therein to extend the full height of the-tooth at the posterior or anterior surface thereof. whichever is to face the opposed artificial tooth containing the male member 28. The .wax form is then cast in a manner well known to the art to form the crown with the female slot member 54 integral purposes. It is to be understood that the female slot member is shown in FIGS. 3-5 as a separate member with crosshatching different from the crown 18 only for illustrative purposes In actuality, the crown will be of one consistency and the female member will appear therein as a vertical channel 64, open at its top and bottom ends and having inner ,walls corresponding to the rear wall 56, the sidewalls 58, the front walls 60 and a flared opening corresponding to the lips 66 leading to a throat 62, see FIG. 2.

In use, the partial denture I is removably mounted in the mandible by inserting each male flange member 28 associated vwith each artificial tooth 26 in each female slot member 54 astelescoping action between the male and female members, the

denture can be entirely tissue bearing, so that rotation around the natural crowned abutment tooth and stresses thereon are minimized if not entirely eliminated. Since the female member is entirely open, top and bottom, through the occlusal and gingival surfaces of the crown abutment, it is also self-cleaning. Excessive frictional wear due to rigidity, tissue resorption, lateral and occlusal stresses are thus substantially reduced.

In the event that the male members should become loose in the female member as a result of excessive wear and stresses,

adjustment can be readily effected by moving the male member 28 towards the rear wall 56 of the female member 54 and if additional adjustment is required, the bracing arm can also be tightened. This can be contrasted with the Stern denture attachment shown and described in US. Pat. No. 1,641,557. In that structure, a box socket is fixed in the abutment tooth and a substantially T-shaped shank is fixed to the bridge which fits intothe box socket, the latterbeing closed at its bottom end. Since there is no cantilever spring attached to the T-shaped shank of Stem, it cannot function to absorb stresses and when the shank becomes loose in the box socket, which is often because of the rigidity of the structure, it can only be adjusted by wedging the shank to spread it, which is substantiallya one-time permanent operation.

While the drawings show a tissue bearing partial denture, it will,be understood that it can also be nontissue bearing by providing a shoulder at the gingival edge of the crown of the abutment tooth 16 against which the lower edge of the bracing arm can bear. In addition, although it is preferred that the horizontal portion 30 of the cantilever spring be soldered or welded to a metal saddle, it can also be embedded in a wholly plastic saddle, in which case the horizontal portion 30 is formed with a loop. Also, while the flange member 36 functions best with two flanges 42 on both sides of the vertical portion 32 of the cantilever spring, one such flange can also be used, in which case the profile of the channel 64 of the female slot member 54 will be made to correspond thereto.

FIGS. 79 illustrate variants of the flange members which can be made integral with or otherwise fixedly secured to the vertical portion 32 of the cantilever spring and corresponding female socket members used to form corresponding channels in the abutment tooth crown.

Thus in the modification of FIG. 7, the male member 68 is generally ovular in horizontal cross section and includes transverse portions 70 which extend laterally beyond the diameter,

of the portion 32 and is joined thereto by areduced neck 72.

The female socket member 74 corresponds in contour to the male member 70 and has front edges forming a throat 76 cor-f.

responding to the neck 72, there being oppositely extending.

lips 78 at the throat.

In the modification of FIG. 8, the male member 80 is substantially dovetail in horizontal cross section and. includes inwardly inclined sidewalls 82 which converge to form a reduced neck 84 joining the vertical portion 32 of the cantilever. Corner portions 86 of the male member 80, where the side portions 82 thereof join the rear wall 88, extend laterally beyond the diameter of the portion 32. The female socket member 90 is also dovetail in horizontal cross section and corresponds to the male member 80 forming at its converging front ends a throat 92 receiving the neck 84, there being lips 94 extending in opposite directions from the throat.

In the modification shown in FIG. 9, the male member 96 is substantially circular in horizontal cross section and of diameter substantially the same as that of the portion 32, the male member 96 being joined TO the portion 32 by a reduced neck 98. The female socket member 100 is also substantially circular in horizontal cross section and corresponds to the male member 96, the female socket forming at its front end a reduced throat 102 receiving the neck 98, there being lips 104 which extend in opposite directions from the throat 102.

The use of partial dentures equipped with the modified male and female members shown in FIGS. 7-9 is the same as that described hereinbefore with reference to the form shown in the remaining figures. It will be understood that the instant construction is used wherever the adjacent tooth of the partial denture is to be attached to the crown abutment. It should also be noted that the cantilever spring 28 serves the dual function of a structural member and a means to absorb transverse vibrations. The spring 28 is a bar or rod of uniform cross section so that the stress distribution thereacross will be uniform when a load is applied axially thereto.

While preferred embodiments of the invention have here been shown and described, it will be understood that skilled artisans may make minor variations without departing from the spirit of the invention.

Iclaim:

I. In a removable claspless partial denture construction, a crowned abutment and a partial denture including a saddle, an elongated resilient member having a generally horizontal portion affixed to said saddle and a generally vertical portion extending outside of said saddle and unconnected thereto, a male member carried by said vertical portion and a generally vertical female member in said crowned abutment opening top and bottom through the occlusal and gingival surfaces of the crown and through one vertical face thereof, removably, telescopingly and lockingly retaining said male member therein, said male and female members being unrestricted so as to make the saddle seat on the tissue-bearing surface of the gum.

2. The denture of claim I wherein said resilient member is a substantially L-shaped rod.

3.The denture of claim 1 in which said saddle includes a vertical strut behind and unconnected to said vertical portion of said resilient member, and an arcuate bracing arm at the upper end of said strut adapted to engage said abutment without connection thereto when said male and female members are interlocked.

4. The denture of claim 2 wherein said male member is a flange and said female member corresponds in horizontal cross section to that of said male member so that said male and female members closely interfit.

5. The denture of claim 4 wherein said flange extends beyond the diameter of said resilient rod and is connected to said rod by a reduced neck portion, the corresponding female member including a reduced throat opening through a vertical the corresponding female member including a reduced throat opening through a vertical face of said abutment and embracing said neck portion.

7. The denture of claim 4 wherein said flange is of generally ovular cross section and extends beyond the diameter of said resilient rod and is connected to said rod by a reduced neck portion, the corresponding female member including a reduced throat opening through a vertical face of said abutment and embracing said neck portion.

8. The denture of claim 1 wherein said resilient member is a substantially L-shaped rod and said male member is a rod connected to the vertical portion thereof by a reduced neck portion, said female member corresponding in horizontal cross section to said male member rod and including a reduced throat opening through a vertical face of said abutment and embracing said neck portion when said male and female members telescopingly interlock.

9. A removable claspless partial denture comprising a saddle and artificial teeth, a substantially L-shaped spring rod having a horizontal portion affixed to said saddle and a vertical portion extending along one end tooth but unconnected thereto, a male member connected to said vertical portion by means of a reduced neck, said male member being adapted to telescopingly interlock with a female slot member in a crown abutment, a strut carried by said saddle to one side of but unconnected to said vertical portion of said rod and an arcuate bracing arm at the top of said strut.

10. The denture of claim 9 wherein said male member is a flange member extending beyond the diameter of said vertical portion of said rod.

11. The denture of claim 10 wherein said male member is of generally dovetail, horizontal cross section.

12. The denture of claim 10 wherein said male member is of generally ovular, horizontal cross section.

13. The denture of claim 9 wherein said male member is of generally circular, horizontal cross section. 

1. In a removable claspless partial denture construction, a crowned abutment and a partial denture including a saddle, an elongated resilient member having a generally horizontal portion affixed to said saddle and a generally vertical portion extending outside of said saddle and unconnected thereto, a male member carried by said vertical portion and a generally vertical female member in said crowned abutment opening top and bottom through the occlusal and gingival surfaces of the crown and through one vertical face thereof, removably, telescopingly and lockingly retaining said male member therein, said male and female members being unrestricted so as to make the saddle seat on the tissuebearing surface of the gum.
 2. The denture of claim 1 wherein said resilient member is a substantially L-shaped rod.
 3. The denture of claim 1 in which said saddle includes a vertical strut behind and unconnected to said vertical portion of said resilient member, and an arcuate bracing arm at the upper end of said strut adapted to engage said abutment without connection thereto when said male and female members are interlocked.
 4. The denture of claim 2 wherein said male member is a flange and said female member corresponds in horizontal cross section to that of said male member so that said male and female members closely interfit.
 5. The denture of claim 4 wherein said flange extends beyond the diameter of said resilient rod and is connected to said rod by a reduced neck portion, the corresponding female member including a reduced throat opening through a vertical face of said abutment and embracing said neck portion.
 6. The denture of claim 4 wherein said flange is of dovetail cross section and extends beyond the diameter of said resilient rod and is connected to said rod by a reduced neck portion, the corresponding female member including a reduced throat opening through a vertical face of said abutment and embracing said neck portion.
 7. The denture of claim 4 wherein said flange is of generally ovular cross section and extends beyond the diameter of said resilient rod and is connected to said rod by a reduced neck portion, the corresponding female member including a reduced throat opening through a vertical face of said abutment and embracing said neck portion.
 8. The denture of claim 1 wherein said resilient member is a substantially L-shaped rod and said male member is a rod connected to the vertical portion thereof by a reduced neck portion, said female member corresponding in horizontal cross section to said male member rod and including a reduced throat opening through a vertical face of said abutment and embracing said neck portion when said male and female members telescopingly interlock.
 9. A removable claspless partial denture comprising a saddle and artificial teeth, a substantially L-shaped spring rod having a horizontal portion affixed to said saddle and a vertical portion extending along one end tooth but unconnected thereto, a male member connected to said vertical portion by means of a reduced neck, said male member being adapted to telescopingly interlock with a female slot member in a crown abutment, a strut carried by said saddle to one side of but unconnected to said vertical portion of said rod and an arcuate bracing arm at the top of said strut.
 10. The denture of claim 9 wherein said male member is a flange member extending beyond the diameter of said vertical portion of said rod.
 11. The denture of claim 10 wherein said male member is of generally dovetail, horizontal cross section.
 12. The denture of claim 10 wherein said male member is of generally ovular, horizontal cross section.
 13. The denture of claim 9 wherein said male member is of generally circular, horizontal cross section. 